Description
Tanzanite – Natural Zoisite Mineral from Tanzania
This genuine Tanzanite specimen from Tanzania is a natural variety of the mineral zoisite, carefully selected for colour and collector appeal. Each piece measures approximately 5–15mm, making it ideal for mineral trays, gem study collections, jewellery projects, or compact display cases. The photograph shows an example of the actual specimen you will receive. Please refer to the listing images for full sizing and natural variation within this size range.
Your Tanzanite specimen includes a Certificate of Authenticity lifetime guarantee generic card, confirming it is a 100% genuine natural mineral from Tanzania.
Mineral Species & Chemical Composition
Tanzanite is the blue to violet variety of zoisite, a calcium aluminium hydroxy sorosilicate mineral with the chemical formula:
Ca₂Al₃(SiO₄)(Si₂O₇)O(OH)
Zoisite belongs to the sorosilicate mineral group and crystallises in the orthorhombic crystal system. Tanzanite’s distinctive colour results from trace amounts of vanadium within the crystal structure.
Key mineralogical properties include:
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Mineral Group: Sorosilicate
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Crystal System: Orthorhombic
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Hardness: 6–7 on the Mohs scale
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Lustre: Vitreous
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Transparency: Transparent to translucent
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Cleavage: Perfect in one direction
Geological Formation – Merelani Hills, Tanzania
Tanzanite is found exclusively in northern Tanzania, primarily within the Merelani Hills near Mount Kilimanjaro. It forms in metamorphic environments where aluminium-rich rocks have undergone high pressure and temperature conditions.
The formation process involves complex tectonic activity, which facilitated the interaction of mineral-rich fluids within metamorphic host rocks. This rare geological combination resulted in the development of vanadium-coloured zoisite crystals known commercially as Tanzanite.
Associated minerals in the Merelani deposits may include graphite, diopside, calcite, and garnet. The restricted geographic origin contributes significantly to Tanzanite’s rarity and desirability among collectors.
Colour & Optical Characteristics
Tanzanite is known for its attractive blue to violet hues and its notable pleochroism, meaning it can display different colours when viewed from different angles. Depending on orientation, specimens may show shades of blue, violet, or subtle reddish undertones.
In the 5–15mm size range, individual pieces may display:
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Subtle colour zoning
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Natural crystal faces or fragment surfaces
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Minor inclusions typical of metamorphic formation
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Variations in tone depending on lighting conditions
Some Tanzanite in the gem trade is heat-treated to enhance colour; however, no additional treatments have been applied beyond standard practices unless otherwise stated. Natural variations are part of the stone’s geological character.
Collecting & Display Appeal
Due to its single-source origin and limited geographic occurrence, Tanzanite is highly valued in mineral and gem collections. Its distinctive colour and crystal structure make it suitable for:
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Mineral specimen trays
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Gemology study collections
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Jewellery design
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Educational geology sets
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Collector display cabinets
In some traditions, Tanzanite is spiritually associated with intuition and transformation; these associations are belief-based rather than scientific.
Authenticity & Individual Selection
Each Tanzanite specimen is a carefully chosen genuine mineral from Tanzania. The listing photograph shows an example of the actual specimen you will receive within the stated 5–15mm size range. Please review all images for scale and natural variation in colour and form.
Every piece is supplied with a Certificate of Authenticity lifetime guarantee generic card, confirming its genuine natural origin.
A rare and distinctive variety of zoisite, this Tanzanite specimen represents a unique geological occurrence from Tanzania and offers strong collector interest, striking colour, and mineralogical significance in a compact and versatile size.
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